In motor controlled systems, a motor can be used to move mechanical components a precise distance to obtain precision movement of the components in the operation of a machine. For some machines, the motor control system operates the machine in machine cycles, and during each machine cycle, or group of machine cycles, the mechanical components perform an operation which is repeated for each cycle or group of cycles. One such operation includes the controlled movement of the mechanical components from a starting position to a stopping position, including a return to the starting position. This operation may take place during one or more machine cycles before the operation is repeated.
Typically, the motor control system must be within a certain tolerance for the operation to be performed properly. For certain applications of such motor control systems, the motor control system has an inherent tendency to exceed the desired tolerance as a result of normal wear and tear to the components. This is particularly the case for high speed operations comprising sudden, high speed or high torque movement.
An example of such high speed operations requiring controlled precision movement is found in an inserting machines including apparatus for turning flat articles, such as described in U.S. Pat. Nos. 4,928,807, 5,131,643 and 5,154,405, which are assigned to the assignee of the present invention. The turning apparatus includes means for receiving a serial stream of articles, e.g., an envelope, conveyed from an insertion station, and means for turning the envelope for further processing. It is critical that the turning mechanism be properly synchronized and aligned to ensure that after the envelope is turned 90 degrees the turning mechanism is returned to the correct starting position.
Experience has shown that repeated operation of such turning mechanisms, and other starting and stopping apparatus, causes wear and tear on the mechanical components which requires periodic mechanical adjustment and eventual replacement of the mechanical components. Generally, such adjustments and replacements are done by a qualified service technician who is trained for the particular machine.
It is an object of the present invention to provide a self-adjusting motor positioning system which automatically adjusts for normal wear and tear of the mechanical components.
It is a further object of the present invention to reduce the amount of service calls required to adjust a motor control system into tolerance.